Mankind's 13 Deadliest Diseases

2. Smallpox

An ancient and deadly scourge on humanity, smallpox originated in northeastern Africa and spread via Egyptian merchants into Asia. The disease starts out as a rash that becomes pus-filled blisters that devolve into painful disfiguration, blindness, and death.

After killing millions upon millions of people for over 10,000 years, the disease was largely eradicated after the WHO began a vaccination campaign in 1967. After dispersing hundreds of millions of vaccines, the disease was globally eradicated 10 years later in 1977.